What should be the gap between the piston and cylinder

The engine is four-stroke, carburetor, in-line, with an overhead camshaft. The engine cooling system is liquid, closed type, with forced circulation of liquid. The engine has a combined lubrication system: pressure and splash. Number of cylinders: 4 Cylinder displacement, l: 1.69 Compression ratio: 9.3 Rated power at a crankshaft speed of 5200 rpm,: 58 kW.-(78.9 hp) Cylinder diameter, mm: 82 Piston stroke, mm: 80 Number of valves: 8 Minimum crankshaft rotation speed, rpm: 750-800 Maximum torque at 3400 rpm, N*m: 127 Cylinder operating order: 1-3-4-2 Gasoline octane number: 91-93 Fuel supply system: carburetor Spark plugs: A17DVR, BP6ES(NGK) Weight, kg: 117

The VAZ 21213 engine can be used for installation on VAZ Niva cars: 2121, 21213, 21214, 2131; "Nadezhda" 2120 and their modifications.

This internal combustion engine was developed specifically for the Niva VAZ-21213 car. Based on the center-to-center distance of the cylinders of 95 mm, it can be classified as a group of internal combustion engines installed on rear-wheel drive cars. They were located in the engine compartment along the axis of the car.

Engine cylinder block 21213-1002011 with a center-to-center distance of 95 mm and a height of 214.58-0.1 mm (distance from the axis of rotation of the crankshaft to the upper surface of the block). The nominal diameter of the cylinders is 82mm. TBO dimensions - 82.40 and 82.80. Five classes are defined based on the deviation of the cylinder diameter. The size of each class differs from the previous one by 0.01mm. Classes are designated by letters (A, B, C, D). The cylinder block is marked on the lower surface of the block (see “Cylinder block”).

The engine is equipped with a crankshaft 21213-1005015. According to its parameters, it corresponds to the crankshaft 2103 and provides a piston stroke of 80 mm. (crank radius – 40mm.). The shaft has additional counterweights that reduce vibration. There are two oil supply holes on each crankpin. The diameters of the shaft journals are increased by 0.02 mm. When using standard bearings, this reduction in clearances optimizes the thickness of the oil layer between the shaft journal and the bearing surface. At the same time, reducing clearances improves the dynamic characteristics of the shaft. Crankshaft 21213 is recommended for installation instead of shaft 2103.

A new piston group has been developed for the engine. Piston 21213 is of original design; it has a specific oval hole on the bottom. For piston diameters, classes corresponding to cylinder classes are defined. The hole for the piston pin is 22mm in diameter. In the piston, the hole for the piston pin is offset by 1.2 mm from the piston axis. The piston class marking by diameter and pin hole size is indicated on the piston bottom. The piston pin, 67 mm long, is fixed in the piston with retaining rings. The weight of the piston is 347g. During manufacturing, all pistons are brought to the same weight.

Connecting rod 21213-1004045 has a new design. The length of the connecting rod is 136 mm. Hole sizes: for the connecting rod journal - 47.8 mm; piston pin – 22mm. New bolts were used to fasten the connecting rod cover, ensuring reliability and accuracy of assembly.

The cylinder head 21213-1002011 (for a 1.7-liter engine) is structurally similar to the 21011 head, but has a number of differences. The height of the head 21213 is 111.0mm, which is 1.8mm lower than the head 21011. The size of the combustion chamber is 81x52 mm, volume 30 cm3.

A new camshaft 21213-1006010 has been developed for the engine. The shape of the cams has been changed to increase the intake valve stroke. The valves and valve train from the 2101 engine are used.

The camshaft drive is chain. Double-row bush-roller chain mod. 2103. A new extended tensioner shoe is used.

Changes in the power system - the use of a 21073 Solex carburetor.

The VAZ 21213 engine is equipped with a non-contact ignition system. The ignition distribution sensor 3810.3706 is responsible for creating control pulses for the switch. The ignition system uses a switch model - 3620.3734. Ignition coil - 27.3705.

Tuning options

When refining a Niva engine, a new crankshaft, cylinders and piston system are most often installed.
As a result, the car receives excellent speed characteristics and cross-country ability. There are two types of Niva engine tuning. The first includes chip tuning, and the second includes mechanical modification of the element. Chip tuning includes software upgrades, and is carried out only on new, fuel-injected SUVs. It includes flashing the control unit settings. It is performed by specialists quite quickly - within half an hour, but requires knowledge of software and additional electronic equipment.

Mechanical modifications are possible on any Niva, and this is the most popular type of tuning of a car’s power plant. With its help, you can significantly improve the technical characteristics of vehicles, and it is based on making some changes to the vehicle systems.

Decarbonization of piston rings

If the engine starts to smoke, there is a possibility that there are rings stuck in the piston grooves. Nowadays, there are many different modern means for decarbonizing piston rings, and many drivers use them to restore engine performance. Among the most popular compositions are:

Motorists believe that if the engine starts smoking, you need to use a decarbonizer, and the engine will work as before, without oil consumption and without smoke. Indeed, sometimes these remedies help, but only in cases where the motor has stood motionless for a long time (for example, after winter), and moisture has accumulated in it. If the car is subject to long-term preservation (put in a garage for winter storage), you should remove the spark plugs and pour oil into the cylinders, and plug the spark plug holes with plugs. With such prevention, the spark plugs will not become damp and rust will not accumulate on the sleeves.

But if, after all, a forgetful car owner has not taken preventive measures, you can use a decarbonizer. We get rid of rust in cylinders as follows:

• pull off high-voltage wires;
• unscrew all spark plugs;
• rotate the crankshaft so that all pistons are in the middle position;
• pour 45 ml of liquid into each cylinder, install spark plugs;
• leave the cylinders to “soak” for 6-7 hours;
• why do we turn out the spark plugs, turn the starter a few revolutions so that all the dirt flies out of the engine;
• We put the removed parts back in place and start the engine. At first it may smoke a lot, but then the smoke will go away.

Car owners should remember that decarbonization is not a panacea for all ills, and if the piston rings are worn out, then only replacing them will help.

Main characteristics of internal combustion engine 21213

Volume, cm 3	1690
Main fuel:	gasoline AI-92
Max. power, l. With.	83 (at 5200 rpm)
Max. torque, Nm	127 (at 3000 rpm)
Cylinder block configuration:	in one row
Number of cylinders	4
Number of valves	8
Max. speed, km/h	153
Acceleration time to 100 km/h, sec.	17
Combined fuel consumption	11,5
Econorm	Russia-83
Cylinder diameter, mm	82 with deviation up to 0.05
Piston stroke, mm	80
Repair dimensions of pistons and cylinders, mm:
first repair (marking on the piston - triangle, on the rings - 40)	82.4
second repair (marking on the piston - square, on the rings - 80)	82.8
Repair measurement of the diameter (for boring) of the crankshaft supports	54.52 with deviation up to 0.013
Compression ratio	9,4
Supply system	two-barrel carburetor
Cooling	liquid
Valve mechanism	SOHC
Cylinder block material	cast iron
Presence of liners in cylinders	not provided for by design
Head material	aluminum alloy
Resource before major overhaul, km	80,000 (actual ≈ 120,000 km)
Number of bars	four
Cylinder operating order	1-3-4-2
Max. speed, rpm	8000
Weight, kg:	117

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content .. 11 12 19 .. VAZ-21213 (Niva). Connecting rod and piston group 2.8.1. Features of the device GENERAL INFORMATION Main dimensions of the connecting rod and piston group Marking of the piston and connecting rod Read also:  Body number in detail: how to find out the year of manufacture of a car by VIN code

1 – arrow for orienting the piston in the cylinder; 2 – repair size; 3 – piston class; 4 – hole class for piston pin; 5 – connecting rod class based on the hole for the piston pin; 6 – cylinder number

Places where it is allowed to remove metal when adjusting the mass of the upper and lower connecting rod heads. Piston
The piston is cast aluminum.
During manufacturing, the weight of the pistons is strictly maintained. Therefore, when assembling the engine, it is not necessary to select pistons of the same weight group. According to the outer diameter, the pistons are divided into five classes (A, B, C, D, E) every 0.01 mm. The outer surface of the piston has a complex shape. It is conical in height and oval in cross section. Therefore, it is necessary to measure the piston diameter only in a plane perpendicular to the piston pin, at a distance of 55 mm from the piston bottom. Based on the diameter of the hole for the piston pin, pistons are divided into three classes (1, 2, 3) every 0.004 mm. The classes of piston diameters and holes for the piston pin are marked on the bottom of the piston (see Fig. Marking of the piston and connecting rod). Repair size pistons are manufactured with an outer diameter increased by 0.4 and 0.8 mm. The bottoms of these pistons are marked in the form of a triangle or square. The triangle corresponds to an increase in the outer diameter by 0.4 mm, and the square - by 0.8 mm. The arrow on the piston crown shows how to properly orient the piston when installing it into the cylinder. It should be directed towards the camshaft drive. Piston pin
The piston pin is steel, hollow, floating type, i.e.
rotates freely in the piston bosses and connecting rod bushing. The pin is secured in the piston by two steel retaining rings. According to the outer diameter, the fingers are divided into three classes every 0.004 mm. The class is marked with paint on the end of the finger: a blue mark is the first class, a green mark is the second class, and a red mark is the third class. Piston rings
Piston rings are made of cast iron.
The upper compression ring has a chrome-plated barrel-shaped outer surface. The lower compression ring is scraper type. Oil scraper ring - with chrome-plated working edges and with an expansion coil spring (expander). Repair size rings are marked digitally “40” or “80”, which corresponds to an increase in the outer diameter by 0.4 or 0.8 mm. Connecting rod – steel, forged. The connecting rod is processed together with the cover and therefore they are individually non-interchangeable. To avoid mixing up the caps and connecting rods during assembly, they are marked with number 6 (see Fig. Marking of the piston and connecting rod) of the cylinder in which they are installed. When assembling, the numbers on the connecting rod and cap should be on the same side. A steel-bronze bushing is pressed into the upper head of the connecting rod. Based on the diameter of the hole in this bushing, the connecting rods are divided into three classes every 0.004 mm (the same as the pistons). The class 5 number is stamped on the upper head of the connecting rod. Based on the mass of the upper and lower heads, connecting rods are divided into classes (see table. Classes of connecting rods based on the mass of the upper and lower heads), marked with paint on the connecting rod rod. Connecting rods of the same weight class must be installed on the engine. The weight of the connecting rods can be adjusted by removing metal from the bosses on the heads to a minimum size of 16, 5 and 35.5 mm (Fig. Places where metal can be removed when adjusting the weight of the upper and lower connecting rod heads). Classes of connecting rods based on the weight of the upper and lower heads

Mass of connecting rod heads, g	Class	Marking color
top			bottom
186 ± 2	519 ± 3	A	White
	525 ± 3	B	Blue
	531 ± 3	C	Red
190 ± 2	519 ± 3	D	Black
	525 ± 3	E	Violet
	531 ± 3	F	Green
194 ± 2	519 ± 3	G	Yellow
	525 ± 3	H	Brown
	531 ± 3	I	Orange

VAZ-21213 (Niva). Selection of piston to cylinder

GENERAL INFORMATION
The calculated gap between the piston and cylinder (for new parts) is 0.025–0.045 mm. It is determined by measuring the parts and is ensured by installing pistons of the same class as the cylinders. The maximum permissible gap (if parts are worn) is 0.15 mm. If a used engine has a gap exceeding 0.15 mm, then it is necessary to re-select the pistons to the cylinders so that the gap is as close as possible to the calculated one. Spare parts include pistons of classes A, C, E. These classes are sufficient to select a piston for any cylinder during engine repair, since pistons and cylinders are divided into classes with a slight overlap of sizes. For example, a class C piston may be suitable for class B and D cylinders.

content .. 11 12 19 ..

Oil pump work

Due to the low engine efficiency and low wear resistance, mechanical tuning of the Niva 4x4 engine is almost mandatory. Such work is called work to change the geometry of the power plant. You should start modifying the power plant by upgrading the carburetor. We do the following:

1. We change jets with an indicator of 1 kam to a jet with an indicator of 2 kam;
2. Renewing the accelerator pump nozzle.

If there is dirt or carbon deposits in the carburetor, we clean it manually. To do this we need a rag, gasoline and physical strength. If the dirt is very stubborn, a high-pressure cleaner or other device designed for washing the car will help. You can also use special “baths” to remove dried dirt from parts. In this way, the fuel supply to the gas distribution mechanism can be significantly improved.

If you are the owner of an injection Niva, then independently modifying the injector is unacceptable. Only a professional with knowledge of software can perform such tuning of the Niva engine.

Lubricant supplied through the oil pump extends engine life. To improve the performance of the oil pump when tuning the Niva engine, you need to take another pump and cut off part of the housing with the parting plane from it. The thickness of this “pancake” should be about 11 cm. Using milling, cut off the excess and leave a thickness of 10 mm.

Next, do the following to remove chamfers on the edges of the teeth:

1. We compress, that is, remove, the drive gears.
2. We trim one of the gears by 0.75 mm on each side.
3. We cut the second gear to 11.5 mm (after trimming).
4. We repeat the operation with the remaining gears (driven).

Let's start working on the body. To do this we do the following:

1. We release the driven gear axis from the housing.
2. We form a longer axis from the drive roller.
3. We insert the resulting axle into the body.
4. We press the narrow gear onto the second drive shaft.
5. Press on the wide gear.
6. We fix the wide driven gear in the housing.
7. We install a narrow gear into the housing.

This sequence will prevent the gears from turning relative to each other. You can also improve the oil receiver of the Vase by cutting it a centimeter from the bottom. After this, we adjust the end gap and connect the entire structure with bolts.

Installation on PRIORU

We will describe the installation of STK pistons on a VAZ (PRIORA), since this particular car is the most purchased in our country and it is this car that most often has problems with the timing belt.

Despite the fact that making a replacement in your yard on your knees is an impossible task, the installation process does not hide any difficulties. First you need to disassemble the engine.

1. We buy plugless pistons, usually the kit can be selected directly to your piston size. That is, if you have an 86 mm piston, then you can also take a plugless piston of 86 mm. However, you need to either know the exact dimensions, or measure them at a service station during disassembly. The cost can vary from 3,000 to 6,000 rubles per set.
2. We disassemble the engine to remove the pistons; it may need to be removed. (Of course, you don’t have to remove it, it’s at the discretion of the masters, there are methods both ways)
3. We remove the piston group and replace it with grooved pistons.
4. Next we assemble the engine.
5. We travel with pleasure.

Many drivers sacrifice power for the sake of greater practicality - you can understand them, especially if you look at the aftermarket. If there is a break, you can fly into such repairs that it won’t seem like much, but this way you are protected.

Repair dimensions of cylinders and pistons of the VAZ 21213 engine during major repairs

Repair cylinder size, mm	Piston and cylinder class	Piston diameter, mm	Cylinder diameter after boring, mm	Cylinder diameter after honing, mm
1 repair
82,4	A	82,34-82,35	82,37-82,38	82,40-82,41
	B	82,35-82,36	82,38-82,39	82,41-82,42
	C	82,36-82,37	82,39-82,40	82,42-82,43
	D	82,37-82,38	82,40-82,41	82,43-82,44
	E	82,38-82,39	82,41-82,42	82,44-82,45
2 repairs
82,8	A	82,74-82,75	82,77-82,78	82,80-82,81
	B	82,75-82,76	82,78-82,79	82,81-82,82
	C	82,76-82,77	82,79-82,80	82,82-82,83
	D	82,77-82,78	82,80-82,81	82,83-82,84
	E	82,78-82,79	82,81-82,82	82,84-82,85

Refinement of the gas distribution mechanism

After replacing the jets and accelerator pump, you can proceed to the second stage of tuning the VAZ-2121 engine. It includes modification of the gas distribution mechanism (GRM), namely, an increase in the diameter of the valves with their subsequent sealing. Such tuning of the Niva 2121 engine will increase the power of the power plant by almost ten percent.

It makes sense to replace the pusher (with a new one with a diameter of at least 1 mm) during the modification of the Niva engine. Work is being done to increase the pusher wells of the intake and exhaust channels. The result of such modification will be especially good for the Niva 4x4.

Subsequent work concerns the replacement of injectors and the control unit itself. Tuning the VAZ-2121 engine will be incomplete unless the standard crankshaft is replaced with an advanced modification, which will significantly increase the power of the power plant. This is due to the increase in piston stroke. It is also recommended to replace the piston rings with new ones.

Such tuning repairs are capable of:

• increase smoothness;
• reduce wear of parts;
• increase power.

Product added to bookmarks!

• Description
• Reviews

Standard crankshaft from the VAZ 2130 1.8L engine (OPP VAZ).

A crankshaft with a stroke of 84 mm (cast iron) is installed in the VAZ 21213 (Niva) and VAZ 2123 (Niva-Chevrolet, CHEVROLET NIVA) block together with

TDMK pistons (82.0 mm - 82.4 mm - 82.8 mm - 84.0 mm), with standard or lightweight connecting rods.

This crankshaft can be installed in the block of a VAZ 2103 (1.5L) and VAZ 2106 (1.6L) without replacing connecting rods and pistons (an accurate calculation of the compression ratio and adjustment of the combustion chamber will be required).

You can increase the engine displacement by: replacing the crankshaft with another one with a larger stroke, increasing the cylinder diameter, or both at the same time. We must not forget that when changing engine volume, it is necessary to increase the volume of the combustion chamber - to compensate for the increase in cylinder volume.

When installing a crankshaft with a long stroke, it is necessary to replace the pistons.

Boring the block cylinders by a significant amount (2 mm) must be approached with caution. For example, when a serial VAZ 21083 block is bored from 82 mm to 84 mm, the engine experiences increased oil consumption. This occurs due to the loss of block rigidity. In this case, it is better to use a special thick-walled block casting. VAZ produces such blocks in small batches.

An increase in engine displacement leads to an increase in maximum torque , but at the same time there is a decrease in maximum power speed. This is due to a decrease in mechanical efficiency. If the increase in volume occurs due to an increase in the diameter of the cylinders, then the contact area between the cylinder walls and the piston with piston rings increases. As a result, friction increases. If the increase in volume occurs due to an increase in the crankshaft stroke, then the average piston speed increases, which leads to the same results.

In any case, an increase in volume leads to a drop in the overall efficiency of the engine.

VAZ engine volume (in cubic cm) depending on the cylinder diameter and piston stroke.

Diameter Stroke, mm cylinder, 80 84 86 88 mm 76.0 1451 1524 1560 1596 76.4 1466 1540 1576 1613 76.8 1476 1556 1593 1630 79.0 1568 1646 1685 17 25 79.4 1584 1663 1702 1742 79.8 1600 1680 1720 1760 80.0 1608 1688 1628 1768 82.0 1689 1774 1816 1858 82.4 1706 1791 1834 1876 82.8 1722 1808 1851 1894 84, 0 1772 1861 1905 1950

Weaknesses of the VAZ 21213 power unit

• Water pump;
• Engine, manual transmission and transfer case oil seals;
• Generator;
• Starter;
• manual transmission;
• Valve cover gasket;
• Cooling system pipe connections;
• Radiator;
• Thermostat;
• Expansion tank;
• Vacuum brake booster.

The water pump (pump) is characterized by frequent failures on new cars after 2,000 km.

Due to poor quality, oil seals require more frequent replacement than required according to the operating manual.

Specifications

The Niva engine has high technical characteristics, and the car itself has increased cross-country ability, since there is a 4x4 option. Over the history of production, the VAZ 2121 has had different engine versions installed, from a carburetor version to an injector and even a diesel version.

So, let's look at the main characteristics of modifications to the Niva power unit:

VAZ 2121

Name	Index
Engine capacity	1.6 liter (1580 cc)
Number of cylinders	4
Number of valves	8
Fuel	Petrol
Injection system	Carburetor
Power	80 horsepower
Fuel consumption	12.2 l/100 km
Cylinder diameter	79 mm
Valve mechanism	SOHC

VAZ 21213

Name	Index
Engine capacity	1.7 liter (1690 cc)
Number of cylinders	4
Number of valves	8
Fuel	Petrol
Injection system	Carburetor
Power	82 horsepower
Fuel consumption	11.0 l/100 km
Cylinder diameter	82 mm
Valve mechanism	SOHC

VAZ 21214

Name	Index
Engine capacity	1.6 liter (1580 cc)
Number of cylinders	4
Number of valves	8
Fuel	Petrol
Injection system	Injector
Power	83 horsepower
Fuel consumption	8.4 l/100 km
Cylinder diameter	82 mm
Econorm	EURO-4
Valve mechanism	SOHC

VAZ 2131

Name	Index
Engine capacity	1.8 liter (1779 cc)
Number of cylinders	4
Number of valves	16
Fuel	Petrol
Injection system	Injector
Power	94 horsepower
Fuel consumption	9.2 l/100 km
Cylinder diameter	82 mm
Econorm	EURO-4
Valve mechanism	SOHC

Engine XUD9SD manufactured by Peugeot

Name	Index
Motor type	Diesel
Engine capacity	1.9 liter (1905 cc)
Number of cylinders	4
Number of valves	8
Fuel	Diesel fuel
Power	75 horsepower
Fuel consumption	7.1 l/100 km

The power units of the VAZ 2121 were equipped with 4-speed manual and 5-speed manual transmissions.

Basics of overhaul

Engine overhauls, except for diesel engines, are carried out typically for all models of Lada power units. So, if you do not take into account the 2131 model with a 16-valve engine, then all versions have a timing chain instead of a belt.

Taking into account the design and manufacturer's manuals, the Niva has a low engine life compared to passenger versions of VAZ cars. So, on average, the mileage before major repairs will be 100-120 thousand km.

Therefore, in order not to spend extra money, many vehicle owners try to repair the engine on their own. Considering the weight of the engine, you will naturally need helpers, at least to remove the engine from the car.

So, what manipulations need to be performed to carry out a major overhaul of the power unit.

1. Removing the engine from the car. To carry out this operation, you will need to disconnect all auxiliary systems and components.
2. Disassembly and diagnostics of the motor. At this stage, the head, pan and valve cover are separated from the cylinder block. Also, you will have to remove the piston mechanism and crankshaft. Don't forget about disassembling the cylinder head.
3. Next comes the process of boring the cylinder block, which is carried out on a special boring and honing wall. Also, the surface of the block is often polished.

The size of the piston group for VAZ 2121 engines with a standard piston size of 82 mm:

Repair	Size
Standard	82.0 mm
1	82.5 mm
2	83.0 mm
3	83.5 mm
4 or more	Block sleeve (installation of sleeves of standard size 82.0 mm)

1. Next, you need to grind the crankshaft to the appropriate size. Also, at this stage, the liners, both main and connecting rod, are tried on.

Causes of oil waste

Well, in general, this is the second question. First you need to find out where the oil goes from the engine if the leak is not visible from the outside? The debate about the natural waste of oil has been going on for many years. There is only one conclusion - if you don’t want the engine to “eat up” the oil, don’t fill it at all! The point is this. The service life of the engine is ensured by good lubrication, and even more so by the lubrication of the piston rings and, as a consequence, the surface of the cylinders in the form of an oil film. So much for natural insanity.

When designing a modern engine, oil loss due to waste is initially 0.1-0.3% of the volume of fuel used . In addition, with different types of operation (river transport, cars, generators), oil burn readings vary significantly! Well, since the engine of the VAZ 21213 is frankly “weak” and, due to the specifics of the vehicle’s operation, operates under increased loads, the passport parameter for oil waste does not last long, after which oil consumption begins to increase significantly. Why? In addition to the mentioned natural burnout, there are several other reasons:

• Oil release through the internal combustion engine ventilation system. The wear of the CPG (cylinder-piston group) directly depends on the pressure of the crankcase gases, whose speeds increase, which contributes to a greater extraction of oil into the atmosphere (in modern cars for “afterburning”);
• A trivial leak in places where engine components do not fit tightly.

Attention: In general, if you see all of the above defects in your car. If you are convinced that the CPG is worn out (by measuring the compression - at least 8 kgf), then replacing the piston rings of the VAZ 21213 is the most economical option for you. In case of such wear of the internal combustion engine, a good owner will, among other things, check the wear of the cylinders, connecting rod liners and, if necessary, replace not only them, but also the entire piston group with valve stem seals. Everything here is limited only by the price of the repair issue.

Engine tuning

Tuning a VAZ 2121 engine is an art. Since the car has the characteristics of an SUV, the engine is tuned accordingly. The air filter duct is installed as high as possible, and the motor from below is protected by a special tray, the purpose of which is not to allow water to pass through.

So, the modification of the Niva’s power unit is designed to increase cross-country ability and traction capabilities, since the vehicle is mainly designed for operation on rough terrain. So, many car enthusiasts bore the power unit in such a way as to add not only horsepower, but also traction.

As practice shows, tuning of VAZ 2121 engines and its modifications is carried out by tuning studios that are well versed in which unit needs to be modified.

Also, in the process of refinement, the ignition system and fuel injection are being modernized. For carburetor engines, an additional carburetor can be installed to increase the amount of fuel entering the combustion chamber.

For injection versions of engines, chip tuning is carried out, which can be aimed at increasing power or the balance between consumption and traction capabilities. Many car enthusiasts install additional sensors that help control the operation of the power unit.

Information on the piston surface

Discussing the question of what markings on pistons mean, it is worth starting with what information the manufacturer puts on the product.

1. Piston size . In some cases, in the markings on the bottom of the piston you can find numbers indicating its size, expressed in hundredths of a millimeter. Example - 83.93. This information means that the diameter does not exceed the specified value, taking into account the tolerance (tolerance groups will be discussed below; they differ for different brands of cars). Measurement is carried out at a temperature of +20°C.
2. Installation gap . Its other name is temperature (since it can change along with changes in the temperature regime in the engine). Designated as Sp. It is given in fractional numbers, meaning millimeters. For example, the marking on the SP0.03 piston indicates that the gap in this case should be 0.03 mm, taking into account the tolerance range.
3. Trademark . Or an emblem. In this way, manufacturers not only identify themselves, but also provide information to craftsmen about whose documentation (product catalogs) should be used when selecting a new piston.
4. Installation direction . This information answers the question - what does the arrow on the piston point to? It “tells” how the piston should be mounted, in particular, the arrow is drawn in the direction of forward movement of the car. On cars where the engine is located at the rear, instead of an arrow, a symbolic crankshaft with a flywheel is often depicted.
5. Casting number . These are numbers and letters that schematically indicate the geometric dimensions of the piston. Typically, such designations can be found on European machines, for which the piston group elements are manufactured by companies such as MAHLE, Kolbenschmidt, AE, Nural and others. To be fair, it is worth noting that casting is now used less and less. However, if you need to identify the piston using this information, then you need to use a paper or electronic catalog of a specific manufacturer.

In addition to these designations, there are also others, and they may differ from one manufacturer to another.